// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_NESTBYVALUE_H
#define EIGEN_NESTBYVALUE_H

namespace Eigen {

namespace internal {
template<typename ExpressionType>
struct traits<NestByValue<ExpressionType>> : public traits<ExpressionType>
{
	enum
	{
		Flags = traits<ExpressionType>::Flags & ~NestByRefBit
	};
};
}

/** \class NestByValue
 * \ingroup Core_Module
 *
 * \brief Expression which must be nested by value
 *
 * \tparam ExpressionType the type of the object of which we are requiring nesting-by-value
 *
 * This class is the return type of MatrixBase::nestByValue()
 * and most of the time this is the only way it is used.
 *
 * \sa MatrixBase::nestByValue()
 */
template<typename ExpressionType>
class NestByValue : public internal::dense_xpr_base<NestByValue<ExpressionType>>::type
{
  public:
	typedef typename internal::dense_xpr_base<NestByValue>::type Base;
	EIGEN_DENSE_PUBLIC_INTERFACE(NestByValue)

	EIGEN_DEVICE_FUNC explicit inline NestByValue(const ExpressionType& matrix)
		: m_expression(matrix)
	{
	}

	EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR inline Index rows() const EIGEN_NOEXCEPT { return m_expression.rows(); }
	EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR inline Index cols() const EIGEN_NOEXCEPT { return m_expression.cols(); }

	EIGEN_DEVICE_FUNC operator const ExpressionType&() const { return m_expression; }

	EIGEN_DEVICE_FUNC const ExpressionType& nestedExpression() const { return m_expression; }

  protected:
	const ExpressionType m_expression;
};

/** \returns an expression of the temporary version of *this.
 */
template<typename Derived>
EIGEN_DEVICE_FUNC inline const NestByValue<Derived>
DenseBase<Derived>::nestByValue() const
{
	return NestByValue<Derived>(derived());
}

namespace internal {

// Evaluator of Solve -> eval into a temporary
template<typename ArgType>
struct evaluator<NestByValue<ArgType>> : public evaluator<ArgType>
{
	typedef evaluator<ArgType> Base;

	EIGEN_DEVICE_FUNC explicit evaluator(const NestByValue<ArgType>& xpr)
		: Base(xpr.nestedExpression())
	{
	}
};
}

} // end namespace Eigen

#endif // EIGEN_NESTBYVALUE_H
